The present invention generally relates to recording of information on a recording sheet and more particularly to the art of ink-jet recording in which visual recording of an image is made on a recording paper by impinging ink droplets thereon.
In the art of ink-jet recording, in which recording of image is made by impinging color ink droplets on a recording paper in response to an image signal, it is important to avoid spreading of the ink on the recording paper. While the problem of spreading of the ink on the recording paper is controlled satisfactorily when a specially produced recording paper is used at the time of ink-jet recording, the problem appears more or less conspicuously when an ordinary recording paper, including those used commonly for xerographic recording of images, is used for the recording medium of the ink-jet recording process.
In order to suppress the foregoing problem of spreading of ink on the recording paper at the time of ink-jet recording, it is proposed to record an ink image once on an intermediate recording medium and then transfer the ink image thus formed to an ordinary recording paper, as disclosed in the Japanese Laid-Open Patent Publication 7-89067. In such a process, it is expected that the ink on the intermediate recording medium increases the viscosity due to the evaporation of the solvent in the ink while the ink is still on the intermediate recording medium.
Unfortunately, this conventional process is inherently ineffective for avoiding the problem of spreading of ink due to the fundamental nature of ink-jet recording, which relies upon the use of an ink containing little resin or solid component. It should be noted that the use of a resin component or solid component in the ink would inevitably invite the problem of clogging of the ink-jet nozzle. Further, the foregoing conventional process has a tendency of incomplete image transfer, and associated therewith, there arises a need of cleaning the intermediate medium each time the intermediate ink image is transferred, for removing the remaining ink from the intermediate medium. Further, the intermediate medium tends to collect particles of the recording paper, while the particles thus collected tend to cause the problem of clogging of the ink-jet nozzle.
Further, there is an ink-jet process, as disclosed in the Japanese Laid-Open Patent Publication 6-92009, which avoids the spreading of ink on the recording paper by projecting a curing agent substantially simultaneously to the ink droplets on the recording paper, such that a droplet of the curing agent hits the portion of the recording paper to which an ink droplet from the ink-jet nozzle is directed. Thereby, the curing agent causes a curing of the ink droplet.
This process, while being able to eliminate the problem of spreading of the ink on the recording paper, has a drawback in that it requires an additional nozzle for projecting the curing agent in alignment with the ink droplets, and the cost of the ink-jet recording is inevitably increased. Further, the foregoing process of using a curing agent generally requires time for the ink to be cured, and the speed of the image recording is inevitably slowed down.
Further, there is an ink-jet process that avoids the spreading of ink on the recording paper as disclosed in the Japanese Laid-Open Patent Publication 5-96720, by uniformly applying an agent on the surface of the recording paper prior to the ink-jet recording, such that the ink droplets landed on the recording paper experience a curing or fixing as a result of contact with the curing agent.
While this process is effective for avoiding the spreading of ink image on the recording paper, the process has a drawback in that the curing agent, being a substance soluble to water or oil, tends to react with the solvent of the ink and the recorded image may be degraded as a result of such a reaction. In other words, the image recorded on the recording paper according to such a process is not stable and may be degraded with time.
Accordingly, it is a general object of the present invention to provide a novel and useful ink-jet image recording method and apparatus wherein the foregoing problems are eliminated.
Another object of the present invention is to provide an ink-jet image recording method and apparatus wherein the problem of spreading of ink on the recording paper is effectively eliminated even when a commonly used, ordinary recording paper is used for recording the ink image.
Another object of the present invention is to provide an ink-jet image recording method and apparatus wherein the image recorded on a recording paper is stable against contacting with water.
Another object of the present invention is to provide an ink-jet image recording method and apparatus wherein the image recorded on a recording paper is preserved with excellent durability.
Another object of the present invention is to provide a method of recording an image on a recording sheet by an ink, said method comprising the steps of:
forming a layer of a substance on said recording sheet, said substance causing an increase of viscosity of said ink when contacted with said ink;
recording an image on said recording sheet by projecting thereto said ink in the form of an ink droplet; and
removing said substance from said recording sheet after said step of recording said image.
Another object of the present invention is to provide an ink-jet image recording apparatus, comprising:
a sheet feed mechanism feeding a recording sheet along a sheet feed path;
an ink-jet recording head provided in said sheet feed path so as to record an image on said recording sheet transported through said sheet feed path, by projecting ink droplets to said recording sheet;
an ink viscosity adjusting mechanism provided in said sheet feed path, said ink viscosity adjusting mechanism providing a substance layer on said recording sheet at an upstream side of said ink-jet recording head, such that said ink-jet recording head records said image through said substance layer;
said ink viscosity adjusting mechanism further removing said substance layer from said recording sheet at a downstream side of said ink-jet recording head after said image is recorded on said recording sheet through said substance layer.
Another object of the present invention is to provide a method of recording an image on a recording sheet by an ink, said method comprising the steps of:
forming a layer of a substance on a recording medium, said substance causing an increase of viscosity of said ink when contacted with said ink;
recording an image on said recording medium by projecting thereto said ink in the form of an ink droplet; and
transferring said image from said recording medium to said recording sheet.
Another object of the present invention is to provide an ink-jet image recording apparatus, comprising:
a sheet feed mechanism feeding a recording sheet along a sheet feed path;
an image transfer medium disposed in said sheet feed path so as to make a contact with said recording sheet transported through said sheet feed path, said image transfer medium being moved along a circuitous path;
an ink-jet recording head provided adjacent to said image transfer medium so as to record an image thereon, by projecting ink droplets to said image transfer medium;
an ink viscosity adjusting mechanism provided on said image transfer medium, said ink viscosity adjusting mechanism providing a substance layer on said image transfer medium at an upstream side of said circuitous path with respect to said ink-jet recording head, such that said ink-jet recording head records said image on said image transfer medium through said substance layer,
wherein said substance layer increases a viscosity of said ink droplet when contacted with said ink droplet.
According to the present invention, the ink droplets increase the viscosity thereof when impinged upon the substance layer, and the problem of spreading of the ink droplets on the surface of the recording sheet is successfully eliminated even when a commonly used, ordinary recording paper is used for the recording sheet. Thereby, a sharply defined, clear image recording becomes possible.
Other objects and further features of the present invention will become apparent from the following detailed description when read in conjunction with the attached drawings.